Chem Lab

| Experiment 2 | Calorimetry | | Chemistry 1310 | 7/21/2013 |

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This experiment is to calibrate a constant pressure calorimeter to experimentally determine a series of heats of reaction that will be used to predict the enthalpy of reaction for another reaction using Hess’ Law and to determine heats of dissolution for a number of ionic salts that will be used to predict lattice energy again by using Hess’ Law. Heat may increase during experiment and undergo exothermic reaction.

Analysis:
Q = m c (Tf - Ti) = 27.9°C – 21.3°C = 6.6°C
Q = (101.81g)(4180kJ/g°C)(6.6°C)
Q = 2808734 kJ
Discussion:
Measurements were relatively accurate and closely linked to quantitative values. When measurement was a little higher, value resulted a little higher. The Styrofoam for this experiment was necessary because it insulates leading to less energy loss to the surrounding of the system. Because there was a change in temperature from the initial and final results, there cannot be an assumption that there was no heat exchange with the surroundings. To improve accuracy of result from this experiment, a better calibration and calorimeter may be used to reduce the amount of heat absorbed during the process.

Conclusion: It is very difficult to get accurate results from this experience due to heat absorption through water and Styrofoam cup which will affect the end results in calculations. A source of error that can derive from using the measuring devices is inaccurately measuring with different instruments ie: using different scales each time to measure calorimeter may give inaccurate results.

Reference: Section 3.3 – 3.5 Olmsted, John III; Williams, Greg; Burk, Robert C. Chemistry, 1st Canadian ed; John Wiley and Sons Ltd: Mississauga, Canada 2010